Different from BGA (Ball Grid Array) types of package, lead-frames have been widely used in packaging power devices and the likes. A metal lead-frame is normally used in a power device with larger power consumption, small size and good heat dissipation. In prior arts, the lead-frame used in the power semiconductor devices is usually made of copper alloy or other metal alloy materials. Under currently technical conditions, the lead-frame made of an aluminum alloy material is extremely difficult to apply in mass production. The problem is that when the aluminum alloy material is punched or bent, it is easy to crack or break.
In addition, aluminum alloy is very easy to be oxidized when it is exposed to air, and the oxides formed on the surface of the aluminum alloy causes poor electrical interconnection between the aluminum lead frame to the semiconductor chips or other functional units.
US patent publication number 2010/0009500 discloses a manufacturing process of a lead-frame made from an aluminum alloy material with a noble metal electroplating layer deposited on the lead-frame. However, noble metal is expensive, so it is not suitable for industrial production on a large scale. As such, this method can only stay at an experimental level or a theoretical level.
In light of these problems, this invention provides a method of manufacturing an aluminum alloy lead frame without noble metal plating and its use to produce a power semiconductor device.